Dyeing with indigoid vat dyestuffs



i 'atented May 20, 1947 9 UNITED STATES PATENT OFFICE 2,420,729 M DYEING WITH INDIGOID VAT DYEs'roFFs' Edward Weber, Winchester Mass assignor, to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of "New York;

No Drawing. ApplicationMarch 30 .1944, V

-. Serial No. 528,771; i

, V l V V This invention relates to a method of dyeing piece-goods comprising animal fibers, and especially woolen piece goods, with indigoid vat dyestuffs. It relates more particularly to an improved method fordyeing piece-goods composed of animal fibers, and especially woolen piecegoods, full shades with indigoid vat dyestuffs, and especially indigo, in an ordinary piece-dye kettle (winch or reel machine).

The dyeing of piece-goods comprising animal fibers withindi'goid vat dyestufis, and. especially indigo, -.presents a number of difficulties which ordinarily are not encountered in the dyeing of cotton and other vegetable fibers. Thus, because of the chemical nature of the animal fibers, it is necessary to avoid the use of strongly alkaline vats. It'l'ias accordingly been the practice to dyewool'en'piece-goods in a weakly alkaline vat (produced by reducing the vat dyestuff with aqueous sodium hydrosulfite and a Weak alkali, such as ammonium hydroxide, sodium carbonate, or the like) which preferably also contains a dispersion assistant (such as a protective colloid or'an organic dispersing agent; for example, glue, gelatin, synthetic organic compounds of the alkyl aryl sulfonate type, and the like).

Further, owing to the relatively low solubility of the leuco compounds of the vat dyestuifs, in such vats, special dyeing procedures requiring the use of special apparatus have been employed heretofore in" order to obtain full shades which are sufficiently even (level) and fast to crocking to be commercially acceptable.

In View of its desirable fastness properties, indigo has been employed extensively for the production of full navy blue shades on wool, especally for military and civilian uniforms. The

production of full navy blue shades on woolen cloth, such as ll-ounce flannel and l6-ounce Melton, presents special difficulties owing to the fact that such woolen cloth is not easily penetrated, andindigo, when .dyed from vatscompatible with wool, is not very soluble in the vat, with the result that dyeings produced. with sufi'ici'ent indigo to give a full navy blue shade are not fast to washing, crocking and rubbing. Hence, many dyers have preferred to dye the raw woolen stock rather than the piece-goods. Others have dyed woolen piece-goods with indigo from an 'ammonia hydrosulfite-glue vat by Working 12 Claims. (01.3%2'5lj I the moth" in the vat," below the surface or jithe dye liquor, in open width by hand (handmawking), orstretched upon framesor on so-called hawking-machines." f

Prior to the present invention it was considerednec'essary to avoidany creasing, folding or wrinklingfof the cloth during the 'sojournof the cloth in the dyebath'inorder to avoid unevenne'ss, streaking, and/or differential fastness'to crocking of the finished cloth. Thisv has restricted the dyeing of woolen piecergoods and related piece-goodsg'comprismg animal fibersto dye houses having the special equipment necessary for such open-width operations,

An object of the present invention is toprovide a method for dyeing piece-goods comprising animal fibers, and. especially woolen, piece-goods, with indigoid vat dyestuffs from. a vati in conventional piece-dyeing apparatus.

Anothercbject of the present invention is .to provide a method for dyeing. piece-goods comprising animal fibers, and especially woolen piece goods, withjndigo' from aweakly alkaline vat in conventional piece -dyeing apparatus; 1

A further object of1the present inventionis to provide a method for dyeing piece-goods comprising animal fibers. in the ropelform with indigoid vat dyestuffs in full shades having good evennessandfastness to cracking.

A specific object of the present invention is to provide a method for dyeing woolen piecegoods in the rope form with indigo from an ammonia-hydrosulfite vat in'full shades having good evenness and fastness to. crocking.

Other objectsof the invention in partwill be obvious? and in part will appear hereinafter.

According tothe present invention, theabove objects are accomplished by dyeing piece-goods comprising animal fibers, and. especially woolen piece-goods, in rope form, in a vat of an indigoid vat dyestuff, the extent of the dyeing being insufiicient to produce a full shade, and bringing the dyeing to full shade by dyeing the. piece,- goods witha wool color. T he wool color may be one which'dyes wool from a neutral or anacid :bath or it maybe a chrome color, When. a'

chrome colqr is used, theidyeing treatment with ;the chrome color is preferably carried'outby the afterchroming process;

If it is attempted to dye woolen piece-goods w full navy blue shades with indigo alone in rope form in conventional piece-dyeing equipment, such as winch or reel machines, amounts of dyestuiT are required which are so large that the dyeings rub off, are not fast to crocking, and are streaked and uneven. According to the present invention, it has been found possible to produce satisfactory full navy blue shades on woolen piece-goods by effecting the major development of the navy blue shades with a restricted amount of indigo which can be applied in conventional piece-dyeing equipment without such deleterious results, and bringing the dyeings to full shade by "filling with wool colors. Good dyeings are obtained by using amounts ranging from about 10 to about 25 pounds of Indigo NAC 20% paste or equivalent (that is, about 2 to about 5 pounds of indigo on the dry basis) per 100 pounds of wool, and. effecting the vatting with from about 1% to 4 /2 pounds of sodium hydrosulfite and from about 1 to about 2%; pounds of sodium hydroxide. The employment of materially less than 10 pounds of 20% Indigo NAC paste or equivalent per 100 pounds of wool is perfectly feasible where weaker shades than a full navy blue are desired; but for full navy blue shades such lesser amounts are undesirable, since they must be filled with so much chrome or other wool colors that the resultant dyeings fail to possess sulficient of the shade and other characteristics peculiar to indigo. On the other hand, it is not generally desirable to employ materially more than pounds of 20% Indigo NAC' paste or equivalent per 100 pounds of wool since difficulties in the complete and satisfactory application of the dyestuff to the wool result.

The dyeing with the wool color may take place prior to the dyeing with the indigoid vat dyestuff or subsequent to the dyeing with the indigoid vat dyestuff. For the production of full shades with indigo on woolen piece-goods, the dyeing with the wool color is preferably carried out with a chrome color and prior to the dyeing with indigo (that is, by chrome color-bottoming) since it has been found that in the method of dyeing in the rope form of the present invention, the application of indigo to a bottom of chrome colors provides a more rapid method of dyeing, and leads to dyeings possessing somewhat superior fastness to rubbing and washing.

The invention will be illustrated by the follOWlng specific example, but it is to be understood that the invention is not limited to the details thereof and that changes may be made Without departing from the scope of the invention.

EXAMPLE Eleven-ounce woolen piece-goods were processed and dyed in rope form in an ordinary piece-dye kettle (winch machine) open to the atmosphere in the following manner, the ratio of the goods to the dyebath or liquor being always maintained at about 1:20. The amount of reagent used in each case is given in terms of 100 pounds of cloth.

Washing The goods were first washed by circulating them for minutes in a bath at 180 F. and composed of water, 2 lbs. of Nacconol NR (a commercial surface-active agent comprising a mixture of alkyl benzene sodium sulfonates derived from kerosene) and 4 lbs. of 26% ammonium hydroxide. The goods were then washed free from alkali with water.

Bottoming with chrome dyes A dyebath was prepared by warming the water in the kettle to F. and adding:

2 oz. of Alizarol Azurine ECA 3 lbs. 8 oz. of Superchrome Blue BC 1 lb. 3 oz. of Superchrome Blue B High Conc.

2 lbs. 8 oz. of Superchrome Red ECB 3 oz. of Superchrome Yellow RN (C. I. 197) 10 lbs. of calcined Glaubers salt (NazSOa) 6 lbs. of 56% acetic acid.

The winch was set in motion, and the dyebath was heated to boiling during one hour. The bath was boiled for an additional hour and then cooled to 160 F. (by displacing part of the exhausted dyebath with cold water) at which point 3 lbs. of sodium bichromate, dissolved in water, were introduced. The bath was reheated to boiling during 15 minutes, and boiled for 45 minutes, after which it was displaced with water. The goods were rinsed until a clear rinse liquor was obtained.

Topping with indigo A stock vat of indigo was prepared by pasting 10 lbs. of Indigo NAC 20% paste (Color IndeX 1177) with a solution of 1 lb. of caustic soda flakes in 5 lbs. of cold water, sprinkling in 1 lb. 11 oz. of sodium hydrosulfite powder, and heating the resulting mixture to F. until reduction of the indigo to the leuco compound Was complete.

A bath was prepared by adding to the water in the kettle:

6 lbs. of 26% ammonium hydroxide, 2 lbs. of animal glue, and 3 lbs. of sodium hydrosulfite. The resulting mixture was heated to 125 F. and the goods were circulated for 10 minutes. The stock vat of indigo was quickly added to the bath, and dyeing was carried out at 125 F. for 20 minutes. Then 10 lbs. of calcined Glaubers salt (Na2SO4) dissolved in 100 lbs. of water, were added slowly during 10 minutes to exhaust the dyebath. The goods were then rinsed and circulated through cold running water until the leuco-indigo was oxidized substantially completely.

The dyed goods thus obtained were scoured with soap in the conventional manner to remove loosely-held indigo, rinsed and dried.

The goods were dyed full and well-penetrated navy blue shades possessing good evenness (level ness) and fastness to crocking.

The temperature of the dyebath is preferably maintained at about 120 to about F. as is usual in dyeing wool with an ammoniacal indigo vat, but other temperatures can be employed.

The exhaustion of the ammoniacal indigo vat (dyebath) is effected with sodium sulfate in the above example. While this results in improved tinctorial strength of the dyeings, as disclosed and Claimed in my application Serial No. 528,772, filed March 30, 1944, it may be accomplished according to methods well known in the art, for example, by adding various acidic substances (e. g., acids or acid salts; such as, ammonium sulfate, bisulfate, formate, acetate, chloride, etc.).

While in the above example woolen piece-goods are dyed first with a chrome color, followed by after-chroming, and then with indigo from an ammonia-hydrosulfite-glue vat, the invention is not limited thereto.

Thus, the invention includes the dyeing of piece-goods comprising proteinous fibers of varidye or a chrome color.

series may be similarly employed instead of indigo; as for example:

Vat Orange R-Color Index No. 1217.

Vat Red Violet RH-Color Index No. 1212.

Vat Pink FFAm. Assoc. Textile Chemists and Colorists, VolfXIX (1942) page 523.

Brilliant Indigo 4BR,Color Index No. 1184.

Brilliant Indigo KMRColor Index No. 1183.

The indigo or other indigoid vat dyestufi may be applied from an ammonia-hydrosulfite-glue vat of the type employed in the above example or from other vats suitable for the dyeing of animal fibers with indigoid vat dyestuffs, a number of which are known. Thus, the vat may contain a leuco compound of the vat dyestuff, a hydrosulfite and a non-caustic alkali (e. g., sodium carbonate, an ethanolamine, ethylene diamine, disodium phosphate, etc.). In dyeing woolen piece-goods with indigo in accordance with the present invention, ammonium hydroxide is preferably employed inasmuch as other noncaustic alkalies lead to somewhat weaker dyeings. Preferably the vat also contains a dispersion assistant, which may be animal glue or another dispersion assistant, a number of which are mentioned above.

ihe invention also includes the application of a wool color, as a topping color, to a fabric dyed with an indigoid vat dyestuff. The wool color may be a neutral wool dye, an acid wool When a chrome color is used, the chrome treatment may be carried out in any of the usual ways for the dyeing of animal fibers with chrome colors. As above noted, in the preferred practice of the present invention, the goods are given a preliminary dyeing with a chrome color and are then dyed with the indigoid vat dyestuff.

The relative amounts of indigoid vat dyestufi and wool color necessary for the production of a particular shade can be readily determined by simple test dyeings. Thus, a test dyeing of a sample of woolen cloth may be carried out with the indigoid vat dyestuii in an amount less than sufiicient to produce the particular shade, and the necessary amount of wool color to bring the resulting dyeing to full shade may then be determined by dyeing the resulting sample of indigoid dyed goods with the selected wool color.

I claim:

1. A method of producing full shades with an indigoid vat dyestuif on piece-goods comprising animal fibers which comprises dyeing the piecegoods in rope form in a vat of an indigoid vat dyestuff, the extent or" the dyeing being less than sufficient to produce a full shade, and dyeing the piece-goods with a wool color to.a sufficient extent to produce a full shade with the dyeing of the indigoid vat dyestuff.

2. The method of dyeing piece-goods comprising animal fibers claimed in claim 1, wherein the dyeing with the wool color precedes the dyeing with the indigoid vat dyestufi.

3. A method of producing full shades with indigo on piece-goods comprising animal fibers which comprises dyeing the piece-goods in rope form in an indigo vat, the extent of the dyeing being less than sufficient to produce a full shade, and dyeing the piece-goods with a wool color to a sufiicient extent to produce a full shade with the indigo dyeing.

4. The method of dyeing piece-goods comprising animal fibers claimed in claim 3, wherein the dyeing with the wool color precedes the dyeing with indigo and the wool color is a chrome color. 5. A method of producing full shades with an indigoid vat dyestuii on woolen piece-goods which comprises dyeing the woolen piece-goods in rope form in a vat of an indigoid vat dyestuff, the extent of the dyeing being less than suificient to produce a full shade, and dyeing the woolen piecegoods with a Wool color to a sufiicient extent to produce a full shade with the dyeing of the indigoid vat dyestuif.

6. The method of dyeing piece-goods comprising animal fibers claimed in claim 5, wherein the dyeing with the wool color precedes the dyeing with the indigoid vat dyestuff.

7. A method of producing full shades with an indigold vat dyestufi on woolen piece-goods which comprises dyeing the woolen piece-goods in an acid dyebath containing a chrome color, afterchroming the dyeing, and dyeing the resulting woolen piece-goods in rope form in a vat containing an indigold vat dyestuff in leuco form, a hydrosulfite, ammonium hydroxide and an organic dispersions assistant, the extent of the dyeing with the indigold vat dyestuff being less than sufficient to produce a full shade.

8. A method of producing full shades with indigo on woolen piece-goods which comprises dyeing woolen piece-goods in rope form with indigo from a weakly alkaline vat and with a wool color, the extent of the dyeing with indigo being less than sufficient to produce a full shade.

9. A method of producing full shades with indigo on .woolen piece-goods which comprises dyeing woolen piece-goods in rope form with indigo from an ammonia-hydrosulfite-glue vat, and with a chrome color followed by after-chroming, the extent of the dyeing with indigo being less than sufficient to produce a full shade.

10. The method of dyeing woolen piece-goods in full navy blue shades which comprises dyeing woolen piece-goods with a wool color, rinsing the resulting dyed goods, working the resulting goods in rope form in an ammonia-hydrosulfite indigo vat. and oxidizing leuco-indigo on the goods to indigo, the amount of indigo employed being about 2 pounds to about 5 pounds, on the dry basis, per hundred pounds of wool.

11. The method of dyeing woolen piece-goods in full navy blue shades which comprises working woolen piece-goods in an acid dyebath containing a chrome color, after-chroming the dyed goods,

rinsing the chromed goods, Working the resulting goods in rope form in an ammonia-hydrosulfite indigo vat, and oxidizing leuco-indigo on the goods to indigo, the amount of indigo employed being about 2 pounds to about 5 pounds, on the dry basis, per hundred pounds of wool.

12. The method of dyeing woolen piece-goods in full navy blue shades which comprises working woolen piece-goods in rope form in an acid dyebath containing a chrome color, acetic acid and sodium sulfate, after-chroming the dyed goods with the addition of sodium bichromate to the dyebath, rinsing the chromed goods, working the resulting goods in rope form in an ammoniahydrosulfite-glue indigo vat, and oxidizing leucoindigo on the goods to indigo, the amount of indigo employed being about 2 pounds to about 8 5 pdunds, on the dry basis per hundred pounds Number Name Date of wool.

- 794,050 Sellet July 4, 1905 EDWARD WEBER 1,682,453 WiIIheim Aug, 23, 1923 REFERENCES CITED 5 FOREIGN PATENTS The following references are of record in the Number Country Date file of this patent: 213,266 Great; Britain Jan. 1, 1925 84,974 Germany Jan. 15, 1896 UNITED STATES PATENTS 379,321 Great Britain Aug. 23, 1932 Number Name Date 10 669,189 France July 27, 1929 1,148,966 Hebden Aug. 3, 1915 1,199,273 Iljinsky Sept. 26, 1916 OTHER REFERENCES 143,026 Weiss Dec. 16, 1890 Whittaker: Dyeing with Coal Tar Dyestuffs,

129,753 Scale July 23, 1872 2nd ed., 1926, pp. 129, 130, 131, 140, 141. 

